There is an increasing demand for efficient software licensing management and accurate inventory tracking. Software licensors grant software licenses to software users and track the computers running software legitimately under the licenses. On the other hand, a growing number of enterprises are implementing virtual machine technology to incorporate visualization into their computer environments and to consolidate the server usage. However, emerging virtual machine technology raises new challenges to software licensing.
A virtual machine is an emulation of a computer system that imitates dedicated hardware. The end user of the a virtual machine can have the same user experience on the virtual machine as he or she would have on a dedicated hardware machine. Because virtual machines are software emulations of dedicated hardware machines, it is easy to create snapshots or clones of virtual machines. A snapshot is a copy of a virtual machine at a given point in time. The snapshot can be used to restore the virtual machine to that particular point in time. Therefore, if a software license restricts a virtual machine to use a software application until a certain time point, an exploiter can continue to use the software despite of the time limitation of the license since the virtual machine can be reverted back to an earlier state using a snapshot.
Similarly, multiple clones (copies) of a virtual machine can be made from a single virtual machine. Since it is difficult to track and differentiate between the clones of the virtual machine, an exploiter can run multiple copies of a software application on the clones despite that the software license restricts the usage of the software application to a single machine.
Avoiding exploitation of software licenses can recover lost profits for a software licensor. However, software vendors struggle to implement licensing management technology that takes virtual machine technology into account. It is a challenge to identify and differentiate copies of virtual machine instances for license tracking purpose.